Research in Mental Retardation and Developmental Disabilities at the University of Pennsylvania, Children's Hospital of Philadelphia and The children's Seashore House should greatly benefit from the facilities proposed by the Mental Retardation Research Center. Funds are requested to provide support to seven core units. These units include Administrative Core: supports general management of Center Associates; Epidemiology and Biostatistics Core: provides Center Associates with statistical consultation for project design and data analysis; Genetics Core: provides a centralized molecular biology facility, tissue culture and cytogenetic karyotyping; Behavior Core: aids in the design and collection of behavioral data in human and animal studies, engages in compliance training nd performs cognitive neuropsychological testing; Neuroscience e: provides synaptic neurochemical methods, neuronal cell culture facilities, and mass spectrometry unit for stable isotope studies; Neuropathology Core: provides light, electron microscopic, and cytoarchitectural capacity as well as a brain registry; Neuroimaging Unit: provides quantitative analysis of MRI scans, an MRS Facility, and PET scans and ligands for SPECT studies. These core units will provide services to 40 federally funded research projects with funding of more than $3 million/year, $540,000 from NICHD. total of 53 University faculty members will be affiliated with the MRRC s Center Associates or Center Staff. These faculty represent 18 departments from 5 major University divisions (The University School of Medicine, Veterinary School, Wistar Institute, Children' Hospital and Children's Seashore House). With the support of the proposed MRRC, we expect o enhance research productivity in the area of mental retardation and developmental disabilities at the University of Pennsylvania.